Related Clues:

• Vegas machine
• Display anxiety, in a way
• Letter drop
• Coin aperture
• Type of item perfect for resale
• Horse's motion
• Home of the Brickyard 400
• Ford role in '89
• Opening for a tab
• Long narrow opening
• Flex
• Wear a rut in the rug
• Pigeon-hole
• Mailbox feature
• Jockey's concern